U.S. patent number 7,310,946 [Application Number 10/565,964] was granted by the patent office on 2007-12-25 for circuit arrangement for cooling charge air and method for operating a circuit arrangement of this type.
This patent grant is currently assigned to Behr GmbH & Co. KG. Invention is credited to Stefan Rogg, Annegret Srnik.
United States Patent |
7,310,946 |
Rogg , et al. |
December 25, 2007 |
Circuit arrangement for cooling charge air and method for operating
a circuit arrangement of this type
Abstract
The invention relates to a circuit arrangement (K) comprising a
low-temperature circuit (NK) for cooling charge air (13) that is
fed to a motor (8) in a motor vehicle equipped with a turbocharger.
According to the invention, the charge air (13) is compressed in
two stages in a first low-pressure turbocharger (1) and a second
high-pressure turbocharger (2). To cool the charge air (13) a first
cooler (3) is provided downstream of the low-pressure turbocharger
(1) and upstream of the high-pressure turbocharger (2) and a second
cooler (4) is provided downstream of the high-pressure turbocharger
(2) and upstream of the motor (8). The invention also relates to a
method for operating a circuit arrangement (K) of this type.
Inventors: |
Rogg; Stefan (Stuttgart,
DE), Srnik; Annegret (Esslingen, DE) |
Assignee: |
Behr GmbH & Co. KG
(Stuttgart, DE)
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Family
ID: |
34111881 |
Appl.
No.: |
10/565,964 |
Filed: |
July 15, 2004 |
PCT
Filed: |
July 15, 2004 |
PCT No.: |
PCT/EP2004/007827 |
371(c)(1),(2),(4) Date: |
January 26, 2006 |
PCT
Pub. No.: |
WO2005/012707 |
PCT
Pub. Date: |
February 10, 2005 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060185362 A1 |
Aug 24, 2006 |
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Foreign Application Priority Data
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Jul 31, 2003 [DE] |
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103 35 567 |
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Current U.S.
Class: |
60/599;
123/41.56; 60/612; 123/563; 123/41.01 |
Current CPC
Class: |
F01P
7/165 (20130101); F02B 29/0443 (20130101); F02B
29/0431 (20130101); F02B 29/0412 (20130101); F02B
37/013 (20130101); F01P 2003/182 (20130101); Y02T
10/12 (20130101); Y02T 10/146 (20130101); F01P
2003/187 (20130101); F01P 2005/105 (20130101); F02B
29/0475 (20130101); Y02T 10/144 (20130101); F01P
2003/185 (20130101); F01P 2060/02 (20130101) |
Current International
Class: |
F02B
29/04 (20060101); F01P 1/00 (20060101); F01P
9/00 (20060101); F02B 33/00 (20060101); F02B
33/44 (20060101) |
Field of
Search: |
;60/599,612
;123/562,563,542,41.56,41,41.01,41.05,41.29 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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006 051 |
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Mar 2003 |
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AT |
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006 106 |
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Apr 2003 |
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AT |
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2923852 |
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Dec 1979 |
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DE |
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199 48 220 |
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Jan 2001 |
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DE |
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696 17 090 |
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Jun 2002 |
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DE |
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0 522 471 |
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Jan 1993 |
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EP |
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1270896 |
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Jan 2003 |
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EP |
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1 336 735 |
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Oct 2005 |
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EP |
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2001-342839 |
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Dec 2001 |
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JP |
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2004116489 |
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Apr 2004 |
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JP |
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1546683 |
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Feb 1990 |
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SU |
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WO 2006086211 |
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Aug 2006 |
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WO |
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Primary Examiner: Trieu; Thai-Ba
Attorney, Agent or Firm: Foley & Lardner LLP
Claims
The invention claimed is:
1. A method for operating a circuit arrangement, wherein the
circuit arrangement comprises a low-temperature circuit for cooling
charge air that is fed to an engine in a motor vehicle equipped
with turbochargers, comprising: compressing the charge air in a
first compressing stage with a first low-pressure turbocharger,
cooling the charge air in a first cooling stage using a
low-pressure charge air/coolant cooler provided downstream of the
low-pressure turbocharger and upstream of a second high-pressure
turbocharger, wherein coolant from the low-pressure charge
air/coolant cooler flows into a coolant/air cooler; further
compressing the cooled charge air in a second compressing stage
with the second high-pressure turbocharger; and cooling the further
compressed charge air in a second cooling stage using a
high-pressure charge air/air cooler provided downstream of the
high-pressure turbocharger and upstream of the engine, wherein the
high-pressure charge air/air cooler is configured to use air flow
of cooling air in a main cooling circuit upstream of a main coolant
cooler as seen in a direction of the air flow of the cooling
air.
2. The method for operating a circuit arrangement as claimed in
claim 1, wherein the charge air after the first cooling stage has a
temperature of between 40.degree. C. and 110.degree. C.
3. A circuit arrangement comprising: a low-temperature circuit for
cooling charge air that is fed to an engine in a motor vehicle
equipped with turbochargers, wherein the low-temperature circuit
comprises: a first low-pressure turbocharger for compressing the
charge air in a first compressing stage; a second high pressure
turbocharger for compressing the charge air in a second compressing
stage; a first cooler provided downstream of the low-pressure
turbocharger and upstream of the high-pressure turbocharger for
cooling the charge air in a first cooling stage; a second cooler
provided downstream of the high-pressure turbocharger and upstream
of the engine for cooling the charge air in a second cooling stage,
and a third cooler, wherein the third cooler and the second cooler
form a cooling module, wherein a front face of the third cooler
takes up 20% to 50% of a total front surface of the cooling module,
wherein the low-temperature circuit is part of an engine cooling
circuit.
4. The circuit arrangement as claimed in claim 3, wherein the
low-temperature circuit branches off from a pressure side of a pump
from the engine cooling circuit and is fed back to the engine
cooling circuit at an engine outlet.
5. The circuit arrangement as claimed in claim 3, wherein the first
cooler comprises a low-pressure charge air/coolant cooler.
6. The circuit arrangement as claimed in claim 3, wherein the
second cooler comprises a high-pressure charge air/air cooler.
7. The circuit arrangement as claimed in claim 6, wherein the third
cooler is a low-temperature cooler.
8. A circuit arrangement comprising: a low-temperature circuit for
cooling charge air that is fed to an engine in a motor vehicle
equipped with turbochargers, wherein the low-temperature circuit
comprises: a first low-pressure turbocharger for compressing the
charge air in a first compressing stage; a second high pressure
turbocharger for compressing the charge air in a second compressing
stage; a low-pressure charge air/coolant cooler provided downstream
of the low-pressure turbocharger and upstream of the high-pressure
turbocharger for cooling the charge air in a first cooling stage; a
high-pressure charge air/air cooler provided downstream of the
high-pressure turbocharger and upstream of the engine for cooling
the charge air in a second cooling stage, and a third cooler that
receives coolant from the low-pressure charge air/coolant cooler,
wherein the high-pressure charge air/air cooler is configured to
use air flow of cooling air in a main cooling circuit upstream of a
main coolant cooler as seen in a direction of the air flow of the
cooling air.
9. The circuit arrangement as claimed in claim 8, wherein the third
cooler is a low-temperature cooler, and wherein the high-pressure
charge air/air cooler is arranged alongside the low-temperature
cooler.
10. The circuit arrangement as claimed in claim 9, wherein the
low-temperature cooler and the high-pressure charge air/air cooler
form a cooling module, wherein a front face of the low-temperature
cooler takes up 20% to 50% of a total front surface of the cooling
module.
11. The circuit arrangement as claimed in claim 8, wherein the
motor vehicle comprises an engine cooling circuit, wherein the
low-temperature circuit is independent of the engine cooling
circuit and has its own pump for delivering coolant.
12. The circuit arrangement as claimed in claim 11, wherein the
pump in the low-temperature circuit is arranged between the third
cooler and the low-pressure charge air/coolant cooler or between
the low-pressure charge air/coolant cooler and the third
cooler.
13. The circuit arrangement as claimed in claim 8, wherein the
low-temperature circuit is part of an engine cooling circuit.
14. The circuit arrangement as claimed in claim 13, wherein the
low-temperature circuit branches off from a pressure side of a pump
from the engine cooling circuit and is fed back to the engine
cooling circuit at an engine outlet.
15. A circuit arrangement comprising: a low-temperature circuit for
cooling charge air that is fed to an engine in a motor vehicle
equipped with turbochargers, wherein the low-temperature circuit
comprises: a first low-pressure turbocharger for compressing the
charge air in a first compressing stage; a second high pressure
turbocharger for compressing the charge air in a second compressing
stage; a first cooler provided downstream of the low-pressure
turbocharger and upstream of the high-pressure turbocharger for
cooling the charge air in a first cooling stage; a second cooler
provided downstream of the high-pressure turbocharger and upstream
of the engine for cooling the charge air in a second cooling stage,
wherein the second cooler comprises a high-pressure charge air/air
cooler; and a third cooler, wherein the third cooler is a
low-temperature cooler configured such that low-temperature coolant
from the first cooler flows through the low-temperature cooler,
wherein the high-pressure charge air/air cooler is arranged
alongside the low-temperature cooler and, seen in a direction of
air flow of cooling air, upstream of a main coolant cooler.
16. The circuit arrangement as claimed in claim 15, wherein the
low-temperature cooler and the high-pressure charge air/air cooler
form a cooling module, wherein a front face of the low-temperature
cooler takes up 20% to 50% of a total front surface of the cooling
module.
17. The circuit arrangement as claimed in claim 15, wherein the
first cooler comprises a low-pressure charge air/coolant
cooler.
18. The circuit arrangement as claimed in claim 15, wherein the
motor vehicle comprises an engine cooling circuit, wherein the
low-temperature circuit is independent of the engine cooling
circuit and has its own pump for delivering coolant.
19. The circuit arrangement as claimed in claim 18, wherein the
pump in the low-temperature circuit is arranged between the
low-temperature cooler and the first cooler or between the first
cooler and the low-temperature cooler.
20. The circuit arrangement as claimed in claim 15, wherein the
low-temperature circuit is part of an engine cooling circuit.
21. The circuit arrangement as claimed in claim 20, wherein the
low-temperature circuit branches off from a pressure side of a pump
from the engine cooling circuit and is fed back to the engine
cooling circuit at an engine outlet.
Description
BACKGROUND OF THE INVENTION
The invention relates to a circuit arrangement for cooling charge
air in a motor vehicle equipped with a turbocharger, and to a
method for operating a circuit arrangement of this type. According
to the prior art, to increase the power of engines, turbochargers
are used in order to increase the throughput of air in the engine.
In the compression needed for this, the air, designated below as
charge air, is heated because of the compression in the
turbocharger. To compensate for the loss of density associated with
the heating of the charge air, i.e. in order to increase the air
density, air coolers are used which are arranged at the front of
the cooling module and serve for cooling the charge air. The charge
air in this case flows through a heat exchanger, through which
ambient air flows and which is consequently cooled. It is thereby
possible to cool the charge air to a temperature which is
approximately 15 K above the temperature of the ambient air.
It is furthermore known that the cooling of the charge air takes
place via a coolant circuit, for example a low-temperature circuit,
in which the coolant is cooled to very low temperatures. By means
of this cold coolant, the charge air is cooled down to a
predetermined cooling temperature in a charge air/coolant cooler.
For the connection of the low-temperature circuit, there are two
variants, namely an integration of the low-temperature circuit into
a secondary circuit of the engine cooling system or a design in the
form of a separate circuit.
If the engine output is to be further increased, the known
supercharging systems have their limits, with respect to
supercharging rates and response characteristics, at low load.
The object of the invention is to improve a circuit arrangement of
the type mentioned in the introduction.
SUMMARY OF THE INVENTION
According to the invention, a circuit arrangement is proposed
comprising a low-temperature circuit for cooling charge air that is
fed to an engine in a motor vehicle equipped with a turbocharger,
characterized in that the charge air is compressed in two stages in
a first low-pressure turbocharger and a second high-pressure
turbocharger, where, in order to cool the charge air, a first
cooler is provided downstream of the low-pressure turbocharger and
upstream of the high-pressure turbocharger, and a second cooler is
provided downstream of the high-pressure turbocharger and upstream
of the engine. By means of the intermediate cooling downstream of
the first low-pressure turbocharger, it is possible to ensure that
excessively high air temperatures do not arise, as a result of
which the service time of the used components, which are exposed to
the high temperatures, can be increased. The two-stage cooling
exhibits an advantageous dynamic behavior. Since the intermediate
cooling in partial load takes up scarcely any thermal loads, the
coolant contained in the low-temperature circuit is cooled to a low
temperature level just above the ambient temperature. This results
in a substantial cooling power reserve which can be utilized when
switching to high engine load.
The installation space required is relatively small compared to the
known solutions, since, despite the intermediate cooling, there is
only one charge air line to and from the cooling module, and only
one coolant-cooled charge air cooler to be arranged near the
engine.
A low-pressure charge air/coolant cooler is preferably provided for
the first cooling of the charge air, and a high-pressure charge
air/air cooler is provided for the second cooling of the charge
air. In this case, stability problems are avoided in the air-cooled
high-pressure charge air/air cooler particularly through the
intermediate cooling.
The installation space can be utilized optimally by virtue of the
fact that the high-pressure charge air/air cooler is arranged
directly alongside a low-temperature cooler and, seen in the
direction of air flow of the cooling air, upstream of a main
coolant cooler. The front face of the low-temperature cooler takes
up preferably 20% to 50% of the total front surface.
According to a preferred variant, the low-temperature circuit is
part of an engine cooling circuit, but it can also be designed
separately from this, and a control system for cutting down on
costs is not absolutely essential. Also possible is an intermediate
cooling with air and/or a cooling of the charge air downstream of
the second compression stage with the aid of a coolant.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in detail below on the basis of two
illustrative embodiments and with reference to the drawing, in
which:
FIG. 1 shows a circuit arrangement according to the first
illustrative embodiment,
FIG. 2 shows a circuit arrangement according to the second
illustrative embodiment,
FIG. 3 shows a graph which shows the outlet temperature of the
second compressor stage over the outlet temperature of the
intermediate cooling, and
FIG. 4 shows a graph which shows the front face portion of the
low-temperature cooler over the outlet temperature of the
intermediate cooling.
FIG. 1 shows a circuit arrangement K which serves for cooling two
successive turbochargers, namely a low-pressure turbocharger 1 and
a high-pressure turbocharger 2. The charge air designated by
reference label 13 is sucked in from the environment and compressed
in the low-pressure turbocharger 1 in a first stage. In so doing,
the temperature of the charge air 13 increases. To achieve a
further compression without adversely affecting the service life as
a result of overheating of the structural parts in direct or
indirect contact with the charge air 13, which is the case of
aluminum at temperatures starting from about 230.degree. C., the
compressed charge air is cooled in a low-pressure charge
air/coolant cooler 3 which is part of a low-temperature circuit NK.
The charge air 13 after the first cooling stage in the low-pressure
turbocharger 1 may have a temperature of between 40.degree. C. and
110.degree. C. The low-temperature circuit NK is discussed in more
detail below.
After the cooling in the low-pressure charge air/coolant cooler 3,
the charge air 13 passes into the high-pressure turbocharger 2 in
which it is further compressed to its end pressure, which is in
turn associated with heating. In order to increase the charge air
density in the (combustion) engine 8, the hot charge air 13 is
cooled in a charge air/air cooler 4 before being fed to the engine
8. As a result of the intermediate cooling, it is possible to
ensure that the maximum charge air temperatures after the last
turbocharger stage remain limited to a degree which permits the use
of air-cooled charge air coolers (cf. FIG. 3). This is advantageous
in respect of the costs and the available installation space.
The low-pressure charge air/coolant cooler 3 for the intermediate
cooling is arranged near the engine and is supplied by the separate
low-temperature circuit NK. An air cooler, hereinafter referred to
as low-temperature cooler 5, is provided in the low-temperature
circuit NK and is traversed by the low-temperature coolant 14 flow
in connection with the low-pressure charge air/coolant cooler
3.
As is shown in FIG. 1, the low-temperature cooler 5 is arranged
directly next to the high-pressure charge air/air cooler 4, both of
which, seen in the direction of flow of the cooling air 15, are
arranged upstream of a main coolant cooler 6. The air is sucked in
by a fan 7 which is arranged behind the main coolant cooler 6. The
low-temperature cooler 5 is dimensioned such that its end face
takes up between 20% and 50% of the maximum possible end face in
the cooling module (see FIG. 4). Alternatively, the low-temperature
cooler 5 can also be arranged in the air flow upstream of the
air-cooled high-pressure charge air/air cooler 4.
The coolers are in this case arranged in such a way that coolers
which are at a low medium temperature level are positioned in the
cold cooling air stream and coolers which are at a high temperature
level are positioned in the warm cooling air stream.
The low-temperature coolant 14 flows onward to the pump 10, which
ensures circulation of the coolant 14, and from there back to the
low-pressure charge air/coolant cooler 3.
According to the present illustrative embodiment, the
low-temperature coolant circuit NK is not controlled; it can be set
in such a way that the best possible charge air cooling is achieved
but boiling problems in the coolant 14 cannot however occur. The
low-temperature coolant circuit NK contains relatively little
coolant 14. The boiling problems are easily avoided because very
high charge air temperatures do not occur at the outlet of the
first compressor stage.
The engine 8 is cooled by an engine cooling circuit MK in which an
engine coolant 12 flows. The coolant 12 cooled in the main coolant
cooler 6 is fed to the engine 8 via the pump 9. The control of the
cooling performance is effected via a bypass thermostat 11 in a
manner known per se.
FIG. 2 shows a circuit arrangement K according to a second
illustrative embodiment which essentially coincides with that of
the first illustrative embodiment unless otherwise described below.
The same reference labels are used here.
In a departure from the first illustrative embodiment, no separate
low-temperature circuit NK is provided in the second illustrative
embodiment. The coolant 14 is instead branched off from the engine
cooling circuit MK from the pressure side of the pump 9 and is fed
to the low-temperature cooler 5. In the low-temperature cooler 5,
the coolant 14 is sharply cooled and then flows to the
coolant-cooled low-pressure charge air/coolant cooler 3, where it
serves for the intermediate cooling of the charge air 13. The
coolant 14 is then mixed again at the engine outlet with the
coolant stream of the engine cooling circuit MK.
LIST OF REFERENCE LABELS
1 low-pressure turbocharger 2 high-pressure turbocharger 3
low-pressure charge air/coolant cooler 4 high-pressure charge
air/air cooler 5 low-temperature cooler 6 main coolant cooler 7 fan
8 engine 9 pump 10 pump 11 thermostat 12 coolant 13 charge air 14
low-temperature coolant 15 cooling air K circuit arrangement MK
engine cooling circuit NK low-temperature circuit
* * * * *